Medical devices that provide a medical function such as electrical stimulation are often affixed to the body at a position of convenience. This is particularly true for implantable medical devices where the device is implanted in a convenient location that may be some distance from a target site within the body where the medical therapy is to be applied. A medical lead is attached to the medical device and is routed to the target site within the body.
The medical lead for electrical stimulation provides electrical contacts on a proximal end and electrodes on a distal end with conductors inside a lead body where those conductors interconnect proximal contacts to distal electrodes that are in contact with the body tissue. The lead is typically attached to the medical device by the proximal end of the lead being inserted into a bore within a header block of the medical device. The proximal contacts of the lead become electrically coupled to electrical connectors within the header block so that stimulation signals pass from the electrical connectors to the proximal contacts and then through the conductors to the distal electrodes.
To fix the lead within the bore, a set screw within a set screw block of the header block is tightened onto a metal ring on the proximal end of the medical lead that is present within the bore of the header block. While the set screw adequately fixes the position of the proximal end of the lead within the bore of the header block, using a set screw for lead fixation presents some drawbacks. For instance, in most cases a clinician must use a tool to tighten the set screw because the set screw cannot be adequately gripped and because the set screw becomes countersunk within the set screw block as the set screw is tightened. Furthermore, the set screw presents a connection that potentially exposes the interior of the header block to fluid ingress.